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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<span class="sourceLineNo">003</span> * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<span class="sourceLineNo">004</span> * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<span class="sourceLineNo">005</span> * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<span class="sourceLineNo">006</span> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<span class="sourceLineNo">007</span> * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<span class="sourceLineNo">008</span> *<a name="line.8"></a>
<span class="sourceLineNo">009</span> *      http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<span class="sourceLineNo">010</span> *<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<span class="sourceLineNo">012</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<span class="sourceLineNo">013</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<span class="sourceLineNo">014</span> * See the License for the specific language governing permissions and<a name="line.14"></a>
<span class="sourceLineNo">015</span> * limitations under the License.<a name="line.15"></a>
<span class="sourceLineNo">016</span> */<a name="line.16"></a>
<span class="sourceLineNo">017</span>package org.apache.commons.net.util;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import java.util.regex.Matcher;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.util.regex.Pattern;<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>/**<a name="line.22"></a>
<span class="sourceLineNo">023</span> * A class that performs some subnet calculations given a network address and a subnet mask.<a name="line.23"></a>
<span class="sourceLineNo">024</span> * @see "http://www.faqs.org/rfcs/rfc1519.html"<a name="line.24"></a>
<span class="sourceLineNo">025</span> * @author &lt;rwinston@apache.org&gt;<a name="line.25"></a>
<span class="sourceLineNo">026</span> * @since 2.0<a name="line.26"></a>
<span class="sourceLineNo">027</span> */<a name="line.27"></a>
<span class="sourceLineNo">028</span>public class SubnetUtils {<a name="line.28"></a>
<span class="sourceLineNo">029</span><a name="line.29"></a>
<span class="sourceLineNo">030</span>    private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";<a name="line.30"></a>
<span class="sourceLineNo">031</span>    private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,3})";<a name="line.31"></a>
<span class="sourceLineNo">032</span>    private static final Pattern addressPattern = Pattern.compile(IP_ADDRESS);<a name="line.32"></a>
<span class="sourceLineNo">033</span>    private static final Pattern cidrPattern = Pattern.compile(SLASH_FORMAT);<a name="line.33"></a>
<span class="sourceLineNo">034</span>    private static final int NBITS = 32;<a name="line.34"></a>
<span class="sourceLineNo">035</span><a name="line.35"></a>
<span class="sourceLineNo">036</span>    private int netmask = 0;<a name="line.36"></a>
<span class="sourceLineNo">037</span>    private int address = 0;<a name="line.37"></a>
<span class="sourceLineNo">038</span>    private int network = 0;<a name="line.38"></a>
<span class="sourceLineNo">039</span>    private int broadcast = 0;<a name="line.39"></a>
<span class="sourceLineNo">040</span><a name="line.40"></a>
<span class="sourceLineNo">041</span>    /** Whether the broadcast/network address are included in host count */<a name="line.41"></a>
<span class="sourceLineNo">042</span>    private boolean inclusiveHostCount = false;<a name="line.42"></a>
<span class="sourceLineNo">043</span><a name="line.43"></a>
<span class="sourceLineNo">044</span><a name="line.44"></a>
<span class="sourceLineNo">045</span>    /**<a name="line.45"></a>
<span class="sourceLineNo">046</span>     * Constructor that takes a CIDR-notation string, e.g. "192.168.0.1/16"<a name="line.46"></a>
<span class="sourceLineNo">047</span>     * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16"<a name="line.47"></a>
<span class="sourceLineNo">048</span>     * @throws IllegalArgumentException if the parameter is invalid,<a name="line.48"></a>
<span class="sourceLineNo">049</span>     * i.e. does not match n.n.n.n/m where n=1-3 decimal digits, m = 1-3 decimal digits in range 1-32<a name="line.49"></a>
<span class="sourceLineNo">050</span>     */<a name="line.50"></a>
<span class="sourceLineNo">051</span>    public SubnetUtils(String cidrNotation) {<a name="line.51"></a>
<span class="sourceLineNo">052</span>        calculate(cidrNotation);<a name="line.52"></a>
<span class="sourceLineNo">053</span>    }<a name="line.53"></a>
<span class="sourceLineNo">054</span><a name="line.54"></a>
<span class="sourceLineNo">055</span>    /**<a name="line.55"></a>
<span class="sourceLineNo">056</span>     * Constructor that takes a dotted decimal address and a dotted decimal mask.<a name="line.56"></a>
<span class="sourceLineNo">057</span>     * @param address An IP address, e.g. "192.168.0.1"<a name="line.57"></a>
<span class="sourceLineNo">058</span>     * @param mask A dotted decimal netmask e.g. "255.255.0.0"<a name="line.58"></a>
<span class="sourceLineNo">059</span>     * @throws IllegalArgumentException if the address or mask is invalid,<a name="line.59"></a>
<span class="sourceLineNo">060</span>     * i.e. does not match n.n.n.n where n=1-3 decimal digits and the mask is not all zeros<a name="line.60"></a>
<span class="sourceLineNo">061</span>     */<a name="line.61"></a>
<span class="sourceLineNo">062</span>    public SubnetUtils(String address, String mask) {<a name="line.62"></a>
<span class="sourceLineNo">063</span>        calculate(toCidrNotation(address, mask));<a name="line.63"></a>
<span class="sourceLineNo">064</span>    }<a name="line.64"></a>
<span class="sourceLineNo">065</span><a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span>    /**<a name="line.67"></a>
<span class="sourceLineNo">068</span>     * Returns &lt;code&gt;true&lt;/code&gt; if the return value of {@link SubnetInfo#getAddressCount()}<a name="line.68"></a>
<span class="sourceLineNo">069</span>     * includes the network address and broadcast addresses.<a name="line.69"></a>
<span class="sourceLineNo">070</span>     * @since 2.2<a name="line.70"></a>
<span class="sourceLineNo">071</span>     */<a name="line.71"></a>
<span class="sourceLineNo">072</span>    public boolean isInclusiveHostCount() {<a name="line.72"></a>
<span class="sourceLineNo">073</span>        return inclusiveHostCount;<a name="line.73"></a>
<span class="sourceLineNo">074</span>    }<a name="line.74"></a>
<span class="sourceLineNo">075</span><a name="line.75"></a>
<span class="sourceLineNo">076</span>    /**<a name="line.76"></a>
<span class="sourceLineNo">077</span>     * Set to &lt;code&gt;true&lt;/code&gt; if you want the return value of {@link SubnetInfo#getAddressCount()}<a name="line.77"></a>
<span class="sourceLineNo">078</span>     * to include the network and broadcast addresses.<a name="line.78"></a>
<span class="sourceLineNo">079</span>     * @param inclusiveHostCount<a name="line.79"></a>
<span class="sourceLineNo">080</span>     * @since 2.2<a name="line.80"></a>
<span class="sourceLineNo">081</span>     */<a name="line.81"></a>
<span class="sourceLineNo">082</span>    public void setInclusiveHostCount(boolean inclusiveHostCount) {<a name="line.82"></a>
<span class="sourceLineNo">083</span>        this.inclusiveHostCount = inclusiveHostCount;<a name="line.83"></a>
<span class="sourceLineNo">084</span>    }<a name="line.84"></a>
<span class="sourceLineNo">085</span><a name="line.85"></a>
<span class="sourceLineNo">086</span><a name="line.86"></a>
<span class="sourceLineNo">087</span><a name="line.87"></a>
<span class="sourceLineNo">088</span>    /**<a name="line.88"></a>
<span class="sourceLineNo">089</span>     * Convenience container for subnet summary information.<a name="line.89"></a>
<span class="sourceLineNo">090</span>     *<a name="line.90"></a>
<span class="sourceLineNo">091</span>     */<a name="line.91"></a>
<span class="sourceLineNo">092</span>    public final class SubnetInfo {<a name="line.92"></a>
<span class="sourceLineNo">093</span>        private SubnetInfo() {}<a name="line.93"></a>
<span class="sourceLineNo">094</span><a name="line.94"></a>
<span class="sourceLineNo">095</span>        private int netmask()       { return netmask; }<a name="line.95"></a>
<span class="sourceLineNo">096</span>        private int network()       { return network; }<a name="line.96"></a>
<span class="sourceLineNo">097</span>        private int address()       { return address; }<a name="line.97"></a>
<span class="sourceLineNo">098</span>        private int broadcast()     { return broadcast; }<a name="line.98"></a>
<span class="sourceLineNo">099</span><a name="line.99"></a>
<span class="sourceLineNo">100</span>        private int low() {<a name="line.100"></a>
<span class="sourceLineNo">101</span>            return (isInclusiveHostCount() ? network() :<a name="line.101"></a>
<span class="sourceLineNo">102</span>                broadcast() - network() &gt; 1 ? network() + 1 : 0);<a name="line.102"></a>
<span class="sourceLineNo">103</span>        }<a name="line.103"></a>
<span class="sourceLineNo">104</span><a name="line.104"></a>
<span class="sourceLineNo">105</span>        private int high() {<a name="line.105"></a>
<span class="sourceLineNo">106</span>            return (isInclusiveHostCount() ? broadcast() :<a name="line.106"></a>
<span class="sourceLineNo">107</span>                broadcast() - network() &gt; 1 ? broadcast() -1  : 0);<a name="line.107"></a>
<span class="sourceLineNo">108</span>        }<a name="line.108"></a>
<span class="sourceLineNo">109</span><a name="line.109"></a>
<span class="sourceLineNo">110</span>        /**<a name="line.110"></a>
<span class="sourceLineNo">111</span>         * Returns true if the parameter &lt;code&gt;address&lt;/code&gt; is in the<a name="line.111"></a>
<span class="sourceLineNo">112</span>         * range of usable endpoint addresses for this subnet. This excludes the<a name="line.112"></a>
<span class="sourceLineNo">113</span>         * network and broadcast adresses.<a name="line.113"></a>
<span class="sourceLineNo">114</span>         * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1"<a name="line.114"></a>
<span class="sourceLineNo">115</span>         * @return True if in range, false otherwise<a name="line.115"></a>
<span class="sourceLineNo">116</span>         */<a name="line.116"></a>
<span class="sourceLineNo">117</span>        public boolean isInRange(String address) {<a name="line.117"></a>
<span class="sourceLineNo">118</span>            return isInRange(toInteger(address));<a name="line.118"></a>
<span class="sourceLineNo">119</span>        }<a name="line.119"></a>
<span class="sourceLineNo">120</span><a name="line.120"></a>
<span class="sourceLineNo">121</span>        private boolean isInRange(int address) {<a name="line.121"></a>
<span class="sourceLineNo">122</span>            int diff = address - low();<a name="line.122"></a>
<span class="sourceLineNo">123</span>            return (diff &gt;= 0 &amp;&amp; (diff &lt;= (high() - low())));<a name="line.123"></a>
<span class="sourceLineNo">124</span>        }<a name="line.124"></a>
<span class="sourceLineNo">125</span><a name="line.125"></a>
<span class="sourceLineNo">126</span>        public String getBroadcastAddress() {<a name="line.126"></a>
<span class="sourceLineNo">127</span>            return format(toArray(broadcast()));<a name="line.127"></a>
<span class="sourceLineNo">128</span>        }<a name="line.128"></a>
<span class="sourceLineNo">129</span><a name="line.129"></a>
<span class="sourceLineNo">130</span>        public String getNetworkAddress() {<a name="line.130"></a>
<span class="sourceLineNo">131</span>            return format(toArray(network()));<a name="line.131"></a>
<span class="sourceLineNo">132</span>        }<a name="line.132"></a>
<span class="sourceLineNo">133</span><a name="line.133"></a>
<span class="sourceLineNo">134</span>        public String getNetmask() {<a name="line.134"></a>
<span class="sourceLineNo">135</span>            return format(toArray(netmask()));<a name="line.135"></a>
<span class="sourceLineNo">136</span>        }<a name="line.136"></a>
<span class="sourceLineNo">137</span><a name="line.137"></a>
<span class="sourceLineNo">138</span>        public String getAddress() {<a name="line.138"></a>
<span class="sourceLineNo">139</span>            return format(toArray(address()));<a name="line.139"></a>
<span class="sourceLineNo">140</span>        }<a name="line.140"></a>
<span class="sourceLineNo">141</span><a name="line.141"></a>
<span class="sourceLineNo">142</span>        /**<a name="line.142"></a>
<span class="sourceLineNo">143</span>         * Return the low address as a dotted IP address.<a name="line.143"></a>
<span class="sourceLineNo">144</span>         * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.<a name="line.144"></a>
<span class="sourceLineNo">145</span>         *<a name="line.145"></a>
<span class="sourceLineNo">146</span>         * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address<a name="line.146"></a>
<span class="sourceLineNo">147</span>         */<a name="line.147"></a>
<span class="sourceLineNo">148</span>        public String getLowAddress() {<a name="line.148"></a>
<span class="sourceLineNo">149</span>            return format(toArray(low()));<a name="line.149"></a>
<span class="sourceLineNo">150</span>        }<a name="line.150"></a>
<span class="sourceLineNo">151</span><a name="line.151"></a>
<span class="sourceLineNo">152</span>        /**<a name="line.152"></a>
<span class="sourceLineNo">153</span>         * Return the high address as a dotted IP address.<a name="line.153"></a>
<span class="sourceLineNo">154</span>         * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.<a name="line.154"></a>
<span class="sourceLineNo">155</span>         *<a name="line.155"></a>
<span class="sourceLineNo">156</span>         * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address<a name="line.156"></a>
<span class="sourceLineNo">157</span>         */<a name="line.157"></a>
<span class="sourceLineNo">158</span>        public String getHighAddress() {<a name="line.158"></a>
<span class="sourceLineNo">159</span>            return format(toArray(high()));<a name="line.159"></a>
<span class="sourceLineNo">160</span>        }<a name="line.160"></a>
<span class="sourceLineNo">161</span><a name="line.161"></a>
<span class="sourceLineNo">162</span>        /**<a name="line.162"></a>
<span class="sourceLineNo">163</span>         * Get the count of available addresses.<a name="line.163"></a>
<span class="sourceLineNo">164</span>         * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false.<a name="line.164"></a>
<span class="sourceLineNo">165</span>         * @return the count of addresses, may be zero.<a name="line.165"></a>
<span class="sourceLineNo">166</span>         */<a name="line.166"></a>
<span class="sourceLineNo">167</span>        public int getAddressCount()                {<a name="line.167"></a>
<span class="sourceLineNo">168</span>            int count = broadcast() - network() + (isInclusiveHostCount() ? 1 : -1);<a name="line.168"></a>
<span class="sourceLineNo">169</span>            return count &lt; 0 ? 0 : count;<a name="line.169"></a>
<span class="sourceLineNo">170</span>        }<a name="line.170"></a>
<span class="sourceLineNo">171</span><a name="line.171"></a>
<span class="sourceLineNo">172</span>        public int asInteger(String address) {<a name="line.172"></a>
<span class="sourceLineNo">173</span>            return toInteger(address);<a name="line.173"></a>
<span class="sourceLineNo">174</span>        }<a name="line.174"></a>
<span class="sourceLineNo">175</span><a name="line.175"></a>
<span class="sourceLineNo">176</span>        public String getCidrSignature() {<a name="line.176"></a>
<span class="sourceLineNo">177</span>            return toCidrNotation(<a name="line.177"></a>
<span class="sourceLineNo">178</span>                    format(toArray(address())),<a name="line.178"></a>
<span class="sourceLineNo">179</span>                    format(toArray(netmask()))<a name="line.179"></a>
<span class="sourceLineNo">180</span>            );<a name="line.180"></a>
<span class="sourceLineNo">181</span>        }<a name="line.181"></a>
<span class="sourceLineNo">182</span><a name="line.182"></a>
<span class="sourceLineNo">183</span>        public String[] getAllAddresses() {<a name="line.183"></a>
<span class="sourceLineNo">184</span>            int ct = getAddressCount();<a name="line.184"></a>
<span class="sourceLineNo">185</span>            String[] addresses = new String[ct];<a name="line.185"></a>
<span class="sourceLineNo">186</span>            if (ct == 0) {<a name="line.186"></a>
<span class="sourceLineNo">187</span>                return addresses;<a name="line.187"></a>
<span class="sourceLineNo">188</span>            }<a name="line.188"></a>
<span class="sourceLineNo">189</span>            for (int add = low(), j=0; add &lt;= high(); ++add, ++j) {<a name="line.189"></a>
<span class="sourceLineNo">190</span>                addresses[j] = format(toArray(add));<a name="line.190"></a>
<span class="sourceLineNo">191</span>            }<a name="line.191"></a>
<span class="sourceLineNo">192</span>            return addresses;<a name="line.192"></a>
<span class="sourceLineNo">193</span>        }<a name="line.193"></a>
<span class="sourceLineNo">194</span><a name="line.194"></a>
<span class="sourceLineNo">195</span>        /**<a name="line.195"></a>
<span class="sourceLineNo">196</span>         * {@inheritDoc}<a name="line.196"></a>
<span class="sourceLineNo">197</span>         * @since 2.2<a name="line.197"></a>
<span class="sourceLineNo">198</span>         */<a name="line.198"></a>
<span class="sourceLineNo">199</span>        @Override<a name="line.199"></a>
<span class="sourceLineNo">200</span>        public String toString() {<a name="line.200"></a>
<span class="sourceLineNo">201</span>            final StringBuilder buf = new StringBuilder();<a name="line.201"></a>
<span class="sourceLineNo">202</span>            buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]")<a name="line.202"></a>
<span class="sourceLineNo">203</span>                .append(" Netmask: [").append(getNetmask()).append("]\n")<a name="line.203"></a>
<span class="sourceLineNo">204</span>                .append("Network:\t[").append(getNetworkAddress()).append("]\n")<a name="line.204"></a>
<span class="sourceLineNo">205</span>                .append("Broadcast:\t[").append(getBroadcastAddress()).append("]\n")<a name="line.205"></a>
<span class="sourceLineNo">206</span>                 .append("First Address:\t[").append(getLowAddress()).append("]\n")<a name="line.206"></a>
<span class="sourceLineNo">207</span>                 .append("Last Address:\t[").append(getHighAddress()).append("]\n")<a name="line.207"></a>
<span class="sourceLineNo">208</span>                 .append("# Addresses:\t[").append(getAddressCount()).append("]\n");<a name="line.208"></a>
<span class="sourceLineNo">209</span>            return buf.toString();<a name="line.209"></a>
<span class="sourceLineNo">210</span>        }<a name="line.210"></a>
<span class="sourceLineNo">211</span>    }<a name="line.211"></a>
<span class="sourceLineNo">212</span><a name="line.212"></a>
<span class="sourceLineNo">213</span>    /**<a name="line.213"></a>
<span class="sourceLineNo">214</span>     * Return a {@link SubnetInfo} instance that contains subnet-specific statistics<a name="line.214"></a>
<span class="sourceLineNo">215</span>     * @return new instance<a name="line.215"></a>
<span class="sourceLineNo">216</span>     */<a name="line.216"></a>
<span class="sourceLineNo">217</span>    public final SubnetInfo getInfo() { return new SubnetInfo(); }<a name="line.217"></a>
<span class="sourceLineNo">218</span><a name="line.218"></a>
<span class="sourceLineNo">219</span>    /*<a name="line.219"></a>
<span class="sourceLineNo">220</span>     * Initialize the internal fields from the supplied CIDR mask<a name="line.220"></a>
<span class="sourceLineNo">221</span>     */<a name="line.221"></a>
<span class="sourceLineNo">222</span>    private void calculate(String mask) {<a name="line.222"></a>
<span class="sourceLineNo">223</span>        Matcher matcher = cidrPattern.matcher(mask);<a name="line.223"></a>
<span class="sourceLineNo">224</span><a name="line.224"></a>
<span class="sourceLineNo">225</span>        if (matcher.matches()) {<a name="line.225"></a>
<span class="sourceLineNo">226</span>            address = matchAddress(matcher);<a name="line.226"></a>
<span class="sourceLineNo">227</span><a name="line.227"></a>
<span class="sourceLineNo">228</span>            /* Create a binary netmask from the number of bits specification /x */<a name="line.228"></a>
<span class="sourceLineNo">229</span>            int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS);<a name="line.229"></a>
<span class="sourceLineNo">230</span>            for (int j = 0; j &lt; cidrPart; ++j) {<a name="line.230"></a>
<span class="sourceLineNo">231</span>                netmask |= (1 &lt;&lt; 31-j);<a name="line.231"></a>
<span class="sourceLineNo">232</span>            }<a name="line.232"></a>
<span class="sourceLineNo">233</span><a name="line.233"></a>
<span class="sourceLineNo">234</span>            /* Calculate base network address */<a name="line.234"></a>
<span class="sourceLineNo">235</span>            network = (address &amp; netmask);<a name="line.235"></a>
<span class="sourceLineNo">236</span><a name="line.236"></a>
<span class="sourceLineNo">237</span>            /* Calculate broadcast address */<a name="line.237"></a>
<span class="sourceLineNo">238</span>            broadcast = network | ~(netmask);<a name="line.238"></a>
<span class="sourceLineNo">239</span>        } else {<a name="line.239"></a>
<span class="sourceLineNo">240</span>            throw new IllegalArgumentException("Could not parse [" + mask + "]");<a name="line.240"></a>
<span class="sourceLineNo">241</span>        }<a name="line.241"></a>
<span class="sourceLineNo">242</span>    }<a name="line.242"></a>
<span class="sourceLineNo">243</span><a name="line.243"></a>
<span class="sourceLineNo">244</span>    /*<a name="line.244"></a>
<span class="sourceLineNo">245</span>     * Convert a dotted decimal format address to a packed integer format<a name="line.245"></a>
<span class="sourceLineNo">246</span>     */<a name="line.246"></a>
<span class="sourceLineNo">247</span>    private int toInteger(String address) {<a name="line.247"></a>
<span class="sourceLineNo">248</span>        Matcher matcher = addressPattern.matcher(address);<a name="line.248"></a>
<span class="sourceLineNo">249</span>        if (matcher.matches()) {<a name="line.249"></a>
<span class="sourceLineNo">250</span>            return matchAddress(matcher);<a name="line.250"></a>
<span class="sourceLineNo">251</span>        } else {<a name="line.251"></a>
<span class="sourceLineNo">252</span>            throw new IllegalArgumentException("Could not parse [" + address + "]");<a name="line.252"></a>
<span class="sourceLineNo">253</span>        }<a name="line.253"></a>
<span class="sourceLineNo">254</span>    }<a name="line.254"></a>
<span class="sourceLineNo">255</span><a name="line.255"></a>
<span class="sourceLineNo">256</span>    /*<a name="line.256"></a>
<span class="sourceLineNo">257</span>     * Convenience method to extract the components of a dotted decimal address and<a name="line.257"></a>
<span class="sourceLineNo">258</span>     * pack into an integer using a regex match<a name="line.258"></a>
<span class="sourceLineNo">259</span>     */<a name="line.259"></a>
<span class="sourceLineNo">260</span>    private int matchAddress(Matcher matcher) {<a name="line.260"></a>
<span class="sourceLineNo">261</span>        int addr = 0;<a name="line.261"></a>
<span class="sourceLineNo">262</span>        for (int i = 1; i &lt;= 4; ++i) {<a name="line.262"></a>
<span class="sourceLineNo">263</span>            int n = (rangeCheck(Integer.parseInt(matcher.group(i)), -1, 255));<a name="line.263"></a>
<span class="sourceLineNo">264</span>            addr |= ((n &amp; 0xff) &lt;&lt; 8*(4-i));<a name="line.264"></a>
<span class="sourceLineNo">265</span>        }<a name="line.265"></a>
<span class="sourceLineNo">266</span>        return addr;<a name="line.266"></a>
<span class="sourceLineNo">267</span>    }<a name="line.267"></a>
<span class="sourceLineNo">268</span><a name="line.268"></a>
<span class="sourceLineNo">269</span>    /*<a name="line.269"></a>
<span class="sourceLineNo">270</span>     * Convert a packed integer address into a 4-element array<a name="line.270"></a>
<span class="sourceLineNo">271</span>     */<a name="line.271"></a>
<span class="sourceLineNo">272</span>    private int[] toArray(int val) {<a name="line.272"></a>
<span class="sourceLineNo">273</span>        int ret[] = new int[4];<a name="line.273"></a>
<span class="sourceLineNo">274</span>        for (int j = 3; j &gt;= 0; --j) {<a name="line.274"></a>
<span class="sourceLineNo">275</span>            ret[j] |= ((val &gt;&gt;&gt; 8*(3-j)) &amp; (0xff));<a name="line.275"></a>
<span class="sourceLineNo">276</span>        }<a name="line.276"></a>
<span class="sourceLineNo">277</span>        return ret;<a name="line.277"></a>
<span class="sourceLineNo">278</span>    }<a name="line.278"></a>
<span class="sourceLineNo">279</span><a name="line.279"></a>
<span class="sourceLineNo">280</span>    /*<a name="line.280"></a>
<span class="sourceLineNo">281</span>     * Convert a 4-element array into dotted decimal format<a name="line.281"></a>
<span class="sourceLineNo">282</span>     */<a name="line.282"></a>
<span class="sourceLineNo">283</span>    private String format(int[] octets) {<a name="line.283"></a>
<span class="sourceLineNo">284</span>        StringBuilder str = new StringBuilder();<a name="line.284"></a>
<span class="sourceLineNo">285</span>        for (int i =0; i &lt; octets.length; ++i){<a name="line.285"></a>
<span class="sourceLineNo">286</span>            str.append(octets[i]);<a name="line.286"></a>
<span class="sourceLineNo">287</span>            if (i != octets.length - 1) {<a name="line.287"></a>
<span class="sourceLineNo">288</span>                str.append(".");<a name="line.288"></a>
<span class="sourceLineNo">289</span>            }<a name="line.289"></a>
<span class="sourceLineNo">290</span>        }<a name="line.290"></a>
<span class="sourceLineNo">291</span>        return str.toString();<a name="line.291"></a>
<span class="sourceLineNo">292</span>    }<a name="line.292"></a>
<span class="sourceLineNo">293</span><a name="line.293"></a>
<span class="sourceLineNo">294</span>    /*<a name="line.294"></a>
<span class="sourceLineNo">295</span>     * Convenience function to check integer boundaries.<a name="line.295"></a>
<span class="sourceLineNo">296</span>     * Checks if a value x is in the range (begin,end].<a name="line.296"></a>
<span class="sourceLineNo">297</span>     * Returns x if it is in range, throws an exception otherwise.<a name="line.297"></a>
<span class="sourceLineNo">298</span>     */<a name="line.298"></a>
<span class="sourceLineNo">299</span>    private int rangeCheck(int value, int begin, int end) {<a name="line.299"></a>
<span class="sourceLineNo">300</span>        if (value &gt; begin &amp;&amp; value &lt;= end) { // (begin,end]<a name="line.300"></a>
<span class="sourceLineNo">301</span>            return value;<a name="line.301"></a>
<span class="sourceLineNo">302</span>        }<a name="line.302"></a>
<span class="sourceLineNo">303</span><a name="line.303"></a>
<span class="sourceLineNo">304</span>        throw new IllegalArgumentException("Value [" + value + "] not in range ("+begin+","+end+"]");<a name="line.304"></a>
<span class="sourceLineNo">305</span>    }<a name="line.305"></a>
<span class="sourceLineNo">306</span><a name="line.306"></a>
<span class="sourceLineNo">307</span>    /*<a name="line.307"></a>
<span class="sourceLineNo">308</span>     * Count the number of 1-bits in a 32-bit integer using a divide-and-conquer strategy<a name="line.308"></a>
<span class="sourceLineNo">309</span>     * see Hacker's Delight section 5.1<a name="line.309"></a>
<span class="sourceLineNo">310</span>     */<a name="line.310"></a>
<span class="sourceLineNo">311</span>    int pop(int x) {<a name="line.311"></a>
<span class="sourceLineNo">312</span>        x = x - ((x &gt;&gt;&gt; 1) &amp; 0x55555555);<a name="line.312"></a>
<span class="sourceLineNo">313</span>        x = (x &amp; 0x33333333) + ((x &gt;&gt;&gt; 2) &amp; 0x33333333);<a name="line.313"></a>
<span class="sourceLineNo">314</span>        x = (x + (x &gt;&gt;&gt; 4)) &amp; 0x0F0F0F0F;<a name="line.314"></a>
<span class="sourceLineNo">315</span>        x = x + (x &gt;&gt;&gt; 8);<a name="line.315"></a>
<span class="sourceLineNo">316</span>        x = x + (x &gt;&gt;&gt; 16);<a name="line.316"></a>
<span class="sourceLineNo">317</span>        return x &amp; 0x0000003F;<a name="line.317"></a>
<span class="sourceLineNo">318</span>    }<a name="line.318"></a>
<span class="sourceLineNo">319</span><a name="line.319"></a>
<span class="sourceLineNo">320</span>    /* Convert two dotted decimal addresses to a single xxx.xxx.xxx.xxx/yy format<a name="line.320"></a>
<span class="sourceLineNo">321</span>     * by counting the 1-bit population in the mask address. (It may be better to count<a name="line.321"></a>
<span class="sourceLineNo">322</span>     * NBITS-#trailing zeroes for this case)<a name="line.322"></a>
<span class="sourceLineNo">323</span>     */<a name="line.323"></a>
<span class="sourceLineNo">324</span>    private String toCidrNotation(String addr, String mask) {<a name="line.324"></a>
<span class="sourceLineNo">325</span>        return addr + "/" + pop(toInteger(mask));<a name="line.325"></a>
<span class="sourceLineNo">326</span>    }<a name="line.326"></a>
<span class="sourceLineNo">327</span>}<a name="line.327"></a>




























































</pre>
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